To find how many days each person takes to complete the full work, then arrange from smallest to largest.
Case (A): P completes 31 of work in 5 days.
If 31 work takes 5 days, then full work takes:
Days for full work =5×3
=15 days
Case (B): Q completes 61 of work in 4 days.
Days for full work =4×6
=24 days
Case (C): R completes 25% of work in 4 days.
Converting: 25% =10025=41
Days for full work =4×4
=16 days
Case (D): S completes 35% of work in 7 days.
Converting: 35% =10035=207
If 207 of work takes 7 days, then full work takes:
Days for full work =7×720
=20 days
Summary:
P (A): 15 days
Q (B): 24 days
R (C): 16 days
S (D): 20 days
Arranging in ascending order: 15 < 16 < 20 < 24
Therefore: (A), (C), (D), (B)
The correct answer is Option 1.